说明：  SPWM(Sinusoidal PWM)法是一种比较成熟的、使用较广泛的PWM法。冲量相等而形状不同的窄脉冲加在具有惯性的环节上时，其效果基本相同。SPWM法就是以该结论为理论基础，用脉冲宽度按正弦规律变化而和正弦波等效的PWM波形即SPWM波形控制逆变电路中开关器件的通断，使其输出的脉冲电压的面积与所希望输出的正弦波在相应区间内的面积相等，通过改变调制波的频率和幅值则可调节逆变电路输出电压的频率和幅值。
(SPWM (Sinusoidal PWM) method is a mature and widely used PWM method. When a narrow pulse with equal impulse and different shape is added to an inertial link, the effect is basically the same. The SPWM method is based on this conclusion. The switching devices in inverters are controlled by the PWM waveform equivalent to the sinusoidal waveform whose pulse width varies according to the sinusoidal law, that is, the SPWM waveform, so that the area of the output pulse voltage is equal to the area of the desired output sinusoidal wave in the corresponding range. The output voltage of the inverters can be adjusted by changing the frequency and amplitude of the modulated wave. Frequency and amplitude.)